Measurement of the excess carrier lifetime is extremely important in characterizing and prescreening semiconductor materials. In the past, this measurement was often done by a contact technique, attaching electrodes directly to the semiconductor material being tested. A much better technique has more recently been used with noncontact lifetime characterization apparatus.
The current noncontact characterization apparatus in use are very large and complex devices. It takes a skilled operator to operate them correctly and they are slow and cumbersome in operation. A need therefore exists for an improved apparatus for measuring excess carrier lifetime characteristics which overcome the complexity and slowness of the prior designs.